LOS ANGELES (AP) — Nguyen Chi Thien, a Vietnamese dissident poet who spent nearly 30 years in communist prisons in his native country, died in a Southern California hospital Tuesday after a long bout of lung illness, according to a close friend. He was 73.

Thien had contracted tuberculosis while in Vietnamese prisons and doctors were investigating a large mass in his lung in the days before he died, his close friend Hanh Thang-Thai said. The actual cause of his death was unclear.

Thien's former translator, Nguyen Ngoc Bich, says Thien is by far the most famous Vietnamese poet of his generation.

"It's like the passing away of a great symbol for the so-called free Vietnam, people who still believe in freedom and democracy for Vietnam," Bich said.

Thien first went to prison in 1960, after telling Vietnamese high school students that, contrary to their textbooks, the end of World War II was not the result of a Soviet attack, but rather U.S. nuclear attacks in Japan.

He was later imprisoned again because of poems he wrote that decried communist oppression. But due to a lack of evidence, he never went to trial.

In 1977, Thien was released from prison long enough to write down poems he had memorized in captivity, a manuscript that became known as "Flowers of Hell."

The poems were published in Vietnamese after he hand-delivered them to British diplomats at their embassy in Hanoi, Vietnam.

When he exited the embassy, security agents were awaiting him and he was promptly sent back to prison.p

While he was still imprisoned, Thien won the International Poetry Award in Rotterdam in 1985.p
He was released from prison in 1991 and traveled to the United States in 1995, and later France, before settling in Orange County's Little Saigon.

Thien's friend Thang-Thai said she and a group of women cared for him, cooking for him and buying him clothes when he needed it, and that he led a humble life.

"His body was breaking, but he was very, very strong mentally," Thang-Thai said. "Before his death, he said to me, 'Be happy, Hanh.' He was a very special person."